Key biased reed switch for electronic musical instrument



Feb. 28, 1967 MARKOWITZ 3,306,968 KEY BIASED REED SWITCH FOR ELECTRONIC MUSICAL INSTRUMENT Filed Dec. 27, 1965 5a a E l 24 /2 /a 2.9 0 49 I W/ 30 7- 1 L [22 50) v. 42 34 a awzmmfi Z6 36 38 32 i ll /6 I l 4 I K 1400/0 /4 I 40 COA/VSWEW AND/0 E com/m??? INVENTOR. m JEROME MAmrow/rz BY m 52 6mg; W

United States Patent 3,306,968 KEY BIASED REED SWlTCH FOR ELECTRONIC MUSICAL INSTRUMENT Jerome Markowitz, Allentown, Pa., assignor to Allen Organ Company, Inc., Macungie, Pa, a corporation of Pennsylvania Filed Dec. 27, 1963, Ser. No. 333,883 18 Claims. (Cl. 841.04)

In general, this invention relates to a new and improved electronic musical instrument and, more particularly, to apparatus for achieving a random reiteration effect with a manually keyed musical instrument such as an electronic organ to reproduce the tone effect of an Xylophone, a marimba or a mandolin.

In the past, manually keyed electronic musical instruments, such as electronic organs, have utilized many devices to reproduce the reiteration tone effect of Xylophones, marimbas, mandolins and the like. These efforts have been directed to utilizing electronic switches which would periodically interrupt the power to the tone generators producing the musical tone, or periodically interrupt the connection between the tone generators and the audio converters. This electronic on-off system has advantages and disadvantages. One advantage is that it is electronic and, therefore, has no moving parts. However, because of its electronic nature, it is extremely expensive to place an electronic switching system adjacent each keyed tone.

To limit costs, prior art organs utilized a single switching circuit for controlling all of the keys. This also has undesirable features. For example, two notes played simultaneously would reiterate in synchronization. This is not a true reproduction of the sound of the Xylophone, marimba or mandolin. That is, the retieration on these last-mentioned instruments was achieved by a musician, and was thus subject to human random variation for each note. Synchronization of the reiteration was, therefore, extremely abnormal. Accordingly, electronic systems utilizing a single electronic switch to achieve the reiteration effect are not true to the original.

Further, synchronization of the reiteration effect is not musically as pleasing to the ear as would be an extremely small random variation between the effect as produced by each keyed tone of the electronic musical instrument.

Still another problem occurs when utilizing a simple switching circuit such as a flip-flop to achieve reiteration tone effects. This problem exists even where a separate circuit has been provided for each key of the electronic musical instrument. The problem is that when certain keys are struck, the switching circuit can be in the off position. Then, for certain keys, there will be a delay between the actual striking of the key and the production of a note. This nonuniform reiteration effect is extremely undesirable, especially where smooth, fast timing is required during the playing of a composition. This electronic problem could be solved with additional circuitry, but such circuitry would also be necessary for every key, thus materially increasing the cost of the instrument.

When one analyzes the sound of an Xylophone, marimba, mandolin or the like, he becomes conscious of a transient metallic overtone which occurs almost simultaneously with the musical tone produced. This sound is probably due to the metallic clicking of the plectrum as it plucks the strings of the mandolin or the similar sound produced when the hammers strike the bars of a marimba or Xylophone. To produce this transient overtone could be accomplished by separate electronic circuitry, but again the cost might well prove to be prohibitive.

Therefore, it is the general object of this invention to avoid and overcome the foregoing and other difficulties of the prior art practices by the provision of a new and improved electronic musical instrument.

Another object of this invention is the provision of a new and better manually keyed electronic musical instrument capable of producing a reiteration tone effect similar to that produced by an Xylophone, marimba or mandolin.

Still another object of this invention is the provision of a new and better system for incorporating reiteration tone effects in a manually keyed electronic musical instrument which can be simply and easily combined with an already existing instrument.

A further object of this invention is the provision of a new and better manually keyed electronic musical instrument which can produce a reiteration effect for each keyed tone without synchronization of the tones produced by simultaneously played keys.

A still further object of this invention is the provision of a new and more economical manually keyed electronic organ which can produce a reiteration effect for each key on the keyboard without delays so that fast tempo compositions utilizing this effect can be played by the organist.

Still another object of this invention is the provision of a new and better manually keyed electronic organ which can produce a reiteration effect for each key on the keyboard with overtones to enhance the sound and make it more like the sound of an xylophone, marimba, mandolin or the like without the necessity for additional electronic circuitry.

Other objects will appear hereinafter.

For the purpose of illustrating the invention, there are shown in the drawings forms which are presently preferred; it being understood, however, that this invention is not limited to the precise arrangement and instrumentalities shown.

FIGURE 1 is a cross sectional view of one key on a keyboard of an electronic musical instrument, with the circuit thereof shown schematically, incorporating the features of the present invention.

FIGURE 2 is a cross sectional view of a key incorporating a second embodiment of the present invention.

FIGURE 2a is a bottom plan view of the shorting bar portion of the embodiment of FIGURE 2.

FIGURE 3 is a diagrammatic showing of a third embodiment of the present invention incorporated in an electronic organ.

FIGURE 3a is a top plan view of the shorting bar portion of the embodiment of FIGURE 3.

FIGURE 4 is a top plan view of a portion of a keyboard utilizing the second embodiment of the present invention.

In FIGURE 1, there is shown one key of a keyboard ensemble 10 built in accordance with the principles of the present invention. It should be understood that although only one key of the ensemble 10 can be seen in FIGURE 1, it is representative of every other key forming the keyboard and is exactly similar thereto except for the points which will be noted below.

The keyboard ensemble 10 includes a key 12 mounted on a key frame 14 for pivotal movement about a balance The balance rail 16 has an upstanding balance key pin 18 extending through a hole 20 in the key 12. It should be understood that the other keys of the keyboard are exactly similar to the key 12 and are mounted for pivotal movement on the balance rail 16 and have respective balance key pins 18 passing through holes therein.

The key 12 is spring biased by a spring 22 secured between the key frame 14 and the key 12. The key 12 has a plastic head 24 which is normally seen by the organist and is manually actuated having a lower limit of travel determined by a head cushion 26. The other or actuating end 28 of the key 12 has a key cushion 30 at the bottom extreme edge thereof which abuts a conducting leaf spring 32. Leaf spring 32 has one end 34 fixed to the key frame 14 and a second end 36 which is free. Adjacent the free end 36, there is placed an adjustable weight 38. The adjustable weight 38 may be moved along the length of the leaf spring 32, but is preferably adjacent the free end 36 thereof. The key cushion 30* biases the leaf spring 32 from its unstressed position to the position shown in FIG- URE 1 wherein weight 38 abuts a spring cushion 40.

The key spring 22 normally maintains key 12 in the position shown in FIGURE 1 wherein key cushion 30 abuts leaf spring 32. Key spring 22 is slightly stronger than leaf spring 32 to achieve this at rest position.

Adjacent the fixed end 34 of the conducting leaf spring 32, there is provided a contact 42 on the upper surface of the leaf spring 32. The fixed end 34 is mechanically connected to a terminal block 44 and electrically connected to a terminal 46 thereon. Terminal 46 is connected through a conductor 48 to the tone generator 54 associated with key 12. Tone generator 54 is the standard tone generator of an electronic organ, and may include one or more audio frequency oscillators. The audio frequency output signal of the tone generator 54 is fed to a suitable converter 56. The audio converter 56 converts the audio frequency electrical signals from the tone generator 54 into an audible signal by conventional means such as the use of an amplifier and loudspeaker. The tone generator 54 and audio converter 56 are part of a standard electronic organ. It will be understood that variations in the tone generator, such as by use of filters or the like to achieve different tones when desired, are within the scope of the teaching of this invention. Further, the audio converter 56 may he merely a loudspeaker, if the tone generator 54 has sufiicient output to drive a loudspeaker without the need for an amplifier.

A contact 50 is mounted on the terminal block 44 electrically insulated from the leaf spring 32. Contact 50 is spaced above contact 42 and separated therefrom when the leaf spring 32 is in the biased position shown in FIG- URE 1. When the key cushion 30 is raised by depressing key head 24, the leaf spring 32 returns to its unbiased position. The contact 42 abuts contact 50 in the unbiased position of leaf spring 32.

A battery 58 is connected to a terminal 52 on terminal block 44. Terminal 52 is in electrically conducting relation with contact 50. When contacts 42 and 50 are closed, a circuit is completed between battery 58, terminal 52, contact 50, contact 42, leaf spring 32, terminal 46, conductor 48 to tone generator 54. The battery 58 is the power supply for the tone generator 54. For example, it can be the B+ for the oscillator or oscillators forming the tone generator 54. Accordingly, when contact 42 touches contact 50, a tone is produced by the audio converter 56.

It will be understood that an organist pressing down on key head 24 will release the biased spring 32. While the term organist is used throughout the specification, it should be understood that this is merely a convenient way of describing the instrument player. The spring 32 will tend to return to its unbiased position, causing contact between contacts 42 and 50 and the production of an audio output signal. However, the weight 38 will tend to return the leaf spring 32 toward cushion 40, thus breaking the circuit between contacts 42 and 50. Accordingly, the pressing of key head 24 will cause leaf spring 32 to vibrate in accordance with the position of weight 38 along the length thereof, making and breaking the circuit between contacts 42 and 50. This alternate making and breaking of the circuit will produce a reiteration tone effect from the audio converter 56. The period of vibration of the leaf spring 32, determined by the position of the weight 38 and the spring material, determines the frequency of the reiteration effect.

As has been stated previously, the key ensemble and the associated electronic equipment are substantially similar for each key of the keyboard. The only differences are as follows: (a) each key has a different tone generator associated therewith; (b) the audio converter may be a single audio converter for all of the tone generators; and (c) the oscillating leaf springs 32 for each key on the keyboard preferably are designed for periods of oscillation which differ one from another by a small amount. This latter arrangement avoids synchronization of the reiteration effect for two keys which have been depressed simultaneously. Rather, a random reiteration effect results from the adjustment of the weights 38 and the manufacturing variations in the parts making up the mechanical vibrating spring system.

As stated previously, a keyboard manufactured in the manner discussed above produces an interesting musical effect which is considerably more desirable than the repetitive effect of simultaneously sounding notes in synchronization, as has been achieved by prior devices. Further, it will be noted that the depression of key head 24 always causes an initial making or closing of contacts 42 and 50, thus eliminating any delay in the production of a tone. Accordingly, the organist can play fast moving compositions without fear of delays in the sounding of a note.

When the key head 24 is released, spring 22 returns key cushion 38 to the position shown in FIGURE 1, immediately damping leaf spring 32 and forcing weight 38 into abutment with cushion 46. This cuts off the audio output signal from converter 56.

The terminals 52 for each key of the keyboard are connected in series with the battery 58 which supplies power to all of the tone generators of the electronic organ.

The weight 38 of each leaf spring 32 can be moved along the length of the spring by releasing an adjusting screw 60. In this manner, each of the springs 32 associated with each key 12 of the keyboard may have a different frequency of oscillation. This difference should be extremely small, but large enough to prevent synchronization of simultaneously sounding notes.

In FIGURE 2, there is shown a second embodiment of the present invention in which a key 12 is mounted on a suitable balance rail 16 having a balance key pin 18. The key 12 is one of the keys on a keyboard, all of which are similar in the manner discussed with respect to the keys 12 of FIGURE 1.

The actuating end 28' of the key 12 has a leaf spring 62 secured thereto at the fixed end 64. Leaf spring 62 has a free end 66 on which is mounted a weight 68 which can be moved along the length of the spring 62 by releasing adjusting screw 70. It will be understood that the key frame has been eliminated from the showing in FIGURE 2 in the interests of clarity. The spring 62 rests on a cushion 74. At the free end of the spring 62, there is provided a shorting bar 76 for short circuiting three terminals 78, and 82 fixedly mounted immediately above the shorting bar 76. The terminal 78 is connected to a power source, and the terminals 80 and 82 are connected to separate oscillators of a tone generator. The manner of this connection is best seen and is similar to that shown in FIGURE 3.

The system of FIGURE 2 is operative in the following manner:

The key 12' is depressed, lifting the leaf spring 62 from the cushion 74. This causes the leaf spring 62 to oscillate between the positions wherein shorting bar 76 at free end 66 abuts terminals 78, 80 and 82, and a position wherein shorting bar 76 is not in contact with the terminals 78, 80 and 82. The period of oscillation is determined by the physical constants of the spring 62 and the position of the weight 68 along the spring 62. When the key 12' is released, the spring 62 returns to cushion 74 immediately damping the oscillations of the spring 62 and returning shorting bar 76 to the position shown in FIGURE 2 wherein the shorting bar 76 is spaced from the terminals 78, 80 and 82.

It should be further noted that the key operated reiteration tone effect systems of FIGURES l and 2 are, at least to some extent, touch sensitive in that the organist can to some degree determine the period of oscillation of the leaf springs and thus the resultant musical tone can be varied by the application of lesser or greater forces to the key. This is especially true of the embodiment shown in FIGURE 2.

In FIGURE 3, there is shown a schematic diagram of an electronic organ utilizing the principles of the present invention wherein it is not possible or desirable to place the oscillating contacts in the key console. That is, it may be desirable to place the reiterating contacts in a position remote from the keyboard, or it may be impossible because of space limitations for such reiteration contacts to be placed at the key console. Accordingly, the system of FIGURE 3 utilizes a standard organ key 84 which is merely one which makes or breaks an electric circuit. The normal organ key is biased to a position wherein it maintains an electric circuit open. The key 84 is in series with a battery 86 and a relay 88. Pressing of the key 84 energizes the relay 88. Relay 88 has a fixed core 90 which would attract a pivotally mounted actuator 92 adjacent thereto. The relay 88 is positioned at a point remote from the key 84 which is one key of the keyboard. Thus, the actuator 92 acts as a substitute key and is exactly similar in operation to the key 12'.

The actuator 92 is mounted on a suitable pivot 94 and has a leaf spring 96 fixedly secured at one end 98 to the actuator 92. An adjustable weight 100 having an adjusting screw 102 is mounted on the free end 104 of the leaf spring 96. Leaf spring 96 rests on a cushion 106 when key 84 is not depressed. A shorting bar 108 is secured to the bottom surface of the free end 104. Three terminals 110, 112 and 114 are mounted below the shorting bar 108. This will create a delay of one-half cycle between the striking of the note and the making of the tone generator circuit. However, this delay will be uniform for all keys. Terminal 110 is connected to a battery 116 which is the source of power for all of the tone generators of the electronic organ. Terminal 112 is connected to a first audio frequency oscillator 118, and terminal 114 is connected to a second audio frequency oscillator 120. Terminals 112 and 114 are connected to the B+ power supply input terminals for the oscillators 118 and 120. Oscillators 118 and 120 form a tone generator 122. The terminals 110, 112 and 114 are normally electrically insulated from each other. Thus, the battery 116 cannot supply power to the oscillators 118 and 120, and thus there will be no electrical audio frequency output signal from the tone generator 122. The tone generator 122 is normally connected to an audio converter 124 similar to the audio converter 56 of FIGURE 1. Shorting bar 108 short circuits terminals 110, 112 and 114 instantaneously connecting the battery 116 to the oscillators 118 and 120. Accordingly, there is produced an electrical audio frequency signal from the tone generator 122 which is supplied to the audio converter 124.

When the key 84 is depressed, relay 88 draws pivotally mounted actuator 92 towards the core 90, lifting leaf spring 96 from cushion 106. Theleaf spring 96 oscillates causing intermittent abutment of the shorting bar 108 with the terminals 110, 112 and 114. This produces the reiteration tone effect discussed previously. Upon release of key 84, relay 88 releases actuator 92 and the leaf spring 96 is immediately damped by cushion 106. Thus, the present invention can be operated with standard electronic organ keys and a separate reiteration assembly at a position remote from the keyboard. The only loss by such remote positioning over the embodiments shown in FIGURES 1 and 2 is the absence of touch control.

In FIGURE 4, there is shown a keyboard 126 which includes a plurality of keys 12'. Each of the keys 12' has the leaf spring 62 secured to the actuating end 28 thereof. As can be seen, the leaf springs 62 each have an adjustable weight 68 thereon differently spaced so as to provide a different period of vibration for each spring.

Applicant has found that when the embodiment shown in FIGURE 2 is utilized, the mechanical making and breaking of the shorting bar 76 with its associated terminals 78, 8t) and 82 produces a clicking or metallic sound similar to that produced by a plectrutn plucking the string of a mandolin or a hammer hitting the bar of an Xylophone or marimba. Since the switch 76 is adjacent the keyboard 126, this metallic clicking sound will be heard simultaneously with or slightly prior to the sound produced by the audio system of the electronic musical instrument. This effectively enhances the musical effect of the electronic musical instrument and more closely resembles the actual sound which is to be reproduced. Further, it has been found that for the higher notes on the keyboard 126, the shorting bar 76 should be slightly thinner than for the lower notes so that the metallic overtone discussed above will be higher for the higher notes than for the lower notes. This will add to the realistic reproduction of the sound desired. By this apparatus, the need for special circuits to reproduce the metallic sound has been eliminated. Obviously, one utilizing the FIGURE 3 embodiment of the present invention would lose the advantage of these metallic overtones unless the reiterating apparatus was close to the keyboard and not in a remote spot.

In can easily be seen that the present invention contemplates the use of the sound of the mechanical switches actuated by the organ keys to enhance the musical tones produced. This is exactly opposite to the theory now utilized in organ designs which is to substantially suppress the sound of all switches. Thus, the clicking sound of the switches is utilized to enhance the musical effect.

Further, the audio converter 56 shown in FIGURE 1 normally includes one or more speakers. As shown in FIGURE 1, these speakers are placed so as to emanate sound ina direction away from the keyboard. When utilizing the preferred embodiment of FIGURE 2, it was especially noted that when speakers were directed away from the keyboard, the metallic clicking sound of the shorting bar 76 would be heard separate and apart from the output of the speaker system. This creates a stereo effect which is pleasing to the ear and musically desirable.

The present invention may be embodied in other specific fonns without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification :as indicating the scope of the invention.

I claim:

1. Musical apparatus comprising a key, an electrical tone generator for producing audio frequency electrical signals, an audio convertor connected to said tone generator to convert said tone generator audio frequency electrical signals into an audio output signal, reiteration means, said key being operative to control said reiteration means, said reiteration means including a contact and a mechanical actuator for alternately opening and closing said contact, said mechanical actuator including spring means for imparting periodic motion to said actuator, said contact being connected to control said audio output signal of said audio convertor.

2. The musical apparatus of claim 1 wherein said key is normally biased to a first position, said key in said first position controlling said reiteration means whereby said contact prevents :an audio output signal from said audio converter, said key having a second depressed position, said key in said second depressed position initiating vibration of said mechanical switch to alternately allow and prevent said audio output signal from said audio converter to produce a reiteration tone effect.

3. The musical apparatus to claim 2 including damping means, said damping means being operative to dampen said actuator when said key is in said first position. i

4. The musical apparatus of claim 3 wherein said actuator is a spring member fixed at one end, a weight,

said weight being mounted on said spring spaced from said one end.

5. The musical apparatus of claim 4 wherein said spring has an electrically conducting portion, at least one fixed contact spaced from said spring conducting portion, said conducting portion being maintained spaced from said fixed contact when said key is in said first position, said spring conducting portion alternately abutting and being spaced from said fixed contact when said key is in said second position.

6. The electronic musical instrument of claim 1 including a source of electric power, said source being connected to said tone generator through said reiteration mean-s, said audio converter having an audio output signal when said tone generator is electrically connected to said source, said contact electrically connecting and disconnecting said source from said tone generator to control said audio output signal of said audio converter.

7. The musical apparatus of claim 1 wherein said mechanical actuator is mechanically connected to said key, said key being mounted for pivotal movement, said actuator being caused to vibrate Iby pivotal movement of said key, said key being biased to a first position, damping means operative to stop said actuator vibrations when said key is in said first position.

8. The musical apparatus of claim 1 including two contacts, one of said contacts being mechanically driven by said spring means, said spring means comprising an elongated resilient member having a free oscillating portion, said key engaging said resilient member in a first position for preventing said member from oscillating, and said key having a second position for initiating oscillation of said member.

9. The musical apparatus of claim 8 wherein said resilient member is mounted with one end free to oscillate, said key holding the member in a deformed position in said first position.

10. The musical apparatus of claim 1 including two contacts, one of said contacts being mechanically. driven by said springs means, said spring means comprising an elongated resilient member having a free oscillating portion, and electromechanical means for causing said portion to oscillate, said key including means to initiate said electromechanical means.

11. The musical apparatus of claim 10 wherein said resilient member is mounted to pivot about a fulcrum, one end of said member being free to oscillate, said electromechanical means being positioned to pivot said resilient member about said fulcrum.

12. Musical apparatus comprising a key, an electrical tone generator for producing :audio frequency electrical electrical signals, an audio convertor connected to said tone generator to convert said tone generator audio frequency electrical signals into an audio output signal, reiteration means, said key Ibeing operative to control said reiteration means, said reiteration means including contact means comprising two spaced contacts, a mechanical actuator for alternately closing and opening said contact means,- said mechanical actuator including an elongated spring having a free oscillatory portion, one of said switch contacts being on said spring for oscillatory movement therewith, said key engaging said spring in a first position for preventing :said spring from oscillating, said key having a second depressed position for initiating oscillation of said spring, said switch being connected to control said audio output signal of said audio convertor.

13. An electronic musical instrument comprising a keyboard having a plurality of keys thereon, at least one electrical tone generator associated with each key for producing audio frequency electrical signals, audio conversion means connected to said tone generators to convert said tone generator audio frequency electrical signals into an audio output signal, separate reiteration means associated with each of said keys, each of said keys being operative to control the reiteration means associated therewith, each of said reiteration means including a contact means and a mechanical actuator for alternately opening and closing said contacts, said mechanical actuator including spring means for imparting periodic motion to said actuator, each of said contact means being connected to control said audio output signal of said audio convertor.

14. The electronic musical instrument of claim 13 wherein each of said keys has a first position wherein said mechanical actuators are at rest, each of said keys having a second position when said keys are depressed, said keys in said secondposition causing said actuators to oscillate.

15. The electronic musical instrument of claim 14 including actuator adjusting means, said adjusting means being operative to adjust the period of vibration of each transducer to be different from the period of vibration of every other transducer.

16. The electronic musical instrument of claim 13 wherein said contact means includes contacts spaced adjacent said actuator, said actuator controlling said audio output signal of said audio converter by periodically opening and closing said contacts.

17. The electronic musical instrument of claim 16 wherein said tone generators are musically graduated in accordance with a musical scale with respect to each key, said actuator and said contact-s being mechanically varied in size to produce metallic tones upon closure of said contacts which are varied with respect to each key.

18. The electronic musical instrument of claim 16 wherein each of said spring means is a leaf spring having one fixed end secured to one end of each key, said leaf springs having a shorting bar secured to the other free end, said contacts being spaced immediately below said shorting bar.

References Cited by the Examiner UNITED STATES PATENTS 2,213,854 9/1940 Wood 2009O 2,303,564 12/1942 Lovell 84-1.14 2,470,148 5/1949 Demuth 84-1.01 X 2,924,137 2/1960 Peter-son 84-126 3,215,765 11/1965 Miessner 84 ARTHUR GAUSS, Primary Examiner. B P. DA S, Assis dn Examin r. 

1. MUSICAL APPARATUS COMPRISING A KEY, AN ELECTRICAL TONE GENERATOR FOR PRODUCING AUDIO FREQUENCY ELECTRICAL SIGNALS, AN AUDIO CONVERTOR CONNECTED TO SAID TONE GENERATOR TO CONVERT SAID TONE GENERATOR AUDIO FREQUENCY ELECTRICAL SIGNALS INTO AN AUDIO OUTPUT SIGNAL, REITERATION MEANS, SAID KEY BEING OPERATIVE TO CONTROL SAID REITERATION MEANS, SAID REITERATION MEANS INCLUDING A CONTACT AND A MECHANICAL ACTUATOR FOR ALTERNATELY OPENING AND 